1. Add the jackson-databind 2.9.4 library to your project.
2. Create and implement the ObjectMapper object to map all properties of the ContactApp class.
3. Test the file IO and implement decorators according to the Jackson documentation.
   1. You should use @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS) for the BaseContact class.
   2. You should use @JsonIgnore annotations where you do not wish to include the output of a class in a JSON file. For example, the get() methods do not need to be included in an object mapping.
4. Create the saveRecords() method in FileAccessService that writes all records to a JSON file. Implement the readAllRecords() method, which should also be in the FileAccessService class. Overwrite the existing file. Call this method just before exiting the main() program.